Engine for portable pneumatic reversible drilling-machines.



G. SOHOFIELD'. ENGINE FOE PORTABLE PNEUMATIC REVERSIBLE DRILLING MACHINES.

APPLIOATION FILED NOV. 2, 1909.

3 SHEETSSHEET l.

Patented 0013. 24, 1911.

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COLUMBIA P LANOGRAPH Cu" WASHINGTON, D4 c U. SGHOFIELD. ENGINE FOB PORTABLE PNEUMATIC REVERSIBLE DRILLING MACHINES. APPLIOATION FILED NOV. 2, 1909.

. 06,883, Patented Oct. 24, 1911.

3 SHEETS-SHEET 2.

cdLuMBIA PLANnnn/WH Co..wAsHlNflTON, D. C.

G. SO'HOFIELD. ENGINE FOR PORTABLE PNEUMATIC REVERSIBLE DRILLING MACHINES.

3 SHEETS-SHEET 3.

COLUMBIA PLANOGRAPH CO-,WASHXNO'ION, D. c.

Patented Oct. 24, 1911.

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ENGINE FOR PORTABLE PNEUMATIC REVERSIBLE DRILLING-MACHINES.

Specification of ietters Patent.

Patented Got. 2 1, 1911.

Application fi1ed November 2, 1909. Serial No. 525,928.

To all whom it may concern.

Be it known that 1, CHARLES ScHorinLn, a subject of the King of England, residing at Newcastle-upon-Tyne, in the county of Northumberland, in England, have invented certain new and useful Improvements in Engines for Portable Pneumatic Reversible Drilling-lvfachines, of which the following is a specification.

This invention relates to portable pneumatic drilling machines and the object is to considerably simplify the construction and operation of the power transmitting devices from the cylinders to the crank shaft.

With this end in view the invention comprises the novel features of construction and combinations of parts hereinafter fully described and specifically defined in the appended claim.

Embodiments of the invention are represented in the annexed drawings in which Figure 1 is a central section on the line AA of Fig. 2 of a drill having two cylinders. Fig. 2 is a section on the line BB of Fig. 1. Fig. 3 is an end elevation from the right hand side of Fig. 2 with the supply pipe removed. Fig. l is an elevation of a four cylinder drill with the cross-head casing in section. Fig. 5 is a plan view of Fig. 4 partially in section on the line G-C of said Fig. 4:- Fig. 6 is a section on the line D-D of Fig. 2 and Fig. 7 is a sectional plan on the line EE of Fig. 1.

Referring more particularly to the construction shown in Figs. 1, 2, 3, 6 and 7, 2 designates the casing, 3 and 1 the cylinders provided respectively with the rotary valves 5 and 6 operated by eccentrics 7 and 8 respectively on the crank shaft of the apparatus. 9 and 10 designate levers on the tops of valves 5 and 6 to which the eccentrics 7 and 8 are connected by means of rods 9- and 10 The reversing valve 11 is of the D type of slide valve said valve being loosely connected to the inner end of the air pipe or tube 12 of the machine and moved backward and forward on the valve face by turning said air tube through the medium of an eccentric pin 13 on the end of the tube engaging in a slot 14: at the back of the valve.

The valve face 15 consists of a circular disk of suitable thickness fixed in the machine casing 2. There are two ports through the disk at a certain distance apart, one of said ports 16 opens into a chamber 17 in communication with the underside of the cylinder valves 5 and 6, the air passing thence up the center 18 of each valve and through the ports to the cylinders thus driving the drill forward. The other port 19 through the disk 15 opens into a chamber 20 in communioation by means of ports 20 with the outer edge or back 21 of the cylinder valves, and into which the air from the cylinders exhausts when the drill is running forward. Between the two said ports 16 and 19 in the disk is an exhaust port 22 which does not pass through the disk but is in communication with a hole or port 23 in the body of the disk leading to a groove or space 2a in its circumference, and a hole 25 in the casing opposite said groove allows the exhaust to pass into the atmosphere. The casing is shaped to receive an attachment 26 which forms a valve chest, and also serves as a guide, for the air pipe or tube 12, which is fitted into and is free to revolve therein. WVithin the valve chest is a slotted disk or the like 27 which engages and serves as a guide for the D valve, and by turning the air tube, the valve is caused to move to such an extent that either of the two through ports 16 or 19 in the disk can be opened to the air pressure in the valve chest. Therefore if the port 16 which opens into the chamber 17 in communication with the underside of the cylinder valves 5 and 6 is open, the drill will be driven forward and the exhaust will pass through the other port 19. If however, the said port 19 which opens into the chamber 20 in communication with the back of the cylinder valves 5 and 6 is open, the motion of the drill is reversed, and it runs backward. The outer end of the air tube 12 is provided with the usual coupling 28 for attachment to the air main supply. For the purpose of turning, a sleeve or handle 29 encircles the air tube, and is suitably connected thereto.

The engine shown in Figs. 1 to 3 has the two double-acting cylinders 3 and 4L, at right angles to each other and working on the same crank pin 36. 30 designates the piston rod of cylinder 3. The cross-head of this piston rod is composed of one member 31 in one piece with the rod, and another member 32 parallel to the member 31. The two said members are held apart by distance pieces 33, and connected together by bolts 84. 35 is a sliding block on the crank pin 36 and located between the cross-head members 31 and 32. Similarly 37 shows the piston rod of cylinder 4 the two members of the crosshead being designated 38 and 39; the distance pieces designated 40, the bolts 41 and the sliding block 42, the latter being also on the crank pin 36. Both cross-heads slide in guides 43 which are attached to or form part of the crank box. Movement is imparted from the crank 'pin to the crank shaft 44 and fronr the latter. to the drill holder 47 by means of the pinion and spur gears 45 and 46 respectively. A hole 48 for a handle is provided in the casing 2. The engine may also have two pairs of double acting cylinders in the same plane and parallel to each other, the two pistons of one pair working on the same crank pin from opposite sides, as shown in Figs. 4 and 5, which show the arrangement of the cross-heads as common to one pair of cylinders, each of the piston rods being in one piece with one member of the cross-head. 49 and 50 show the upper pair of cylinders, the other pair being immediately below. 51 and 52 are the piston rods respectively of said cylinders. 53 is the cross-head member on rod 51 and 54 the cross-head member on rod 52. 55 shows the sliding block between the cross-head members 53 and 54 and 56 the crank pin. The members of the cross-head for lower pair of cylinders are designated by 57 and 58, 59 being the sliding block therefor and 60 the crank pin.

What I claim as my invention and desire to secure by Letters Patent of the United States is In an engine for portable pneumatic reversible drilling machines, the combination of a pair of power cylinders arranged at right angles to each other, a rotary valve for each cylinder and carrying a Wrist pin on the end thereof, conduits leading from each rotary valve to the opposite ends of each cylinder, a piston in each cylinder and rods for the pistons, a doublecross-head for each piston rod comprising a pair of spaced members, one of the spaced members being integral with the piston rod, spacing sleeves between the ends of said spaced members and connecting bolts passing through said sleeves and the ends of the members, a casing inclosing the crossheads, guides arranged centrally on the inner walls of the casing for guiding the ends of the spaced members of the cross-heads, a block slidably mounted between the spaced members of each cross-head, a crank pin passing through the blocks, means for driving a drill from the crank spindle, eccentrics on the crank spindle, and links connecting the eccentrics and the wrist pins of the rotary valves whereby the rotary valves are operated alternately from the crank, substantially as described.

In witness whereof I have signed this specification in the presence of two Witnesses.

CHARLES SOHOFIELD. Witnesses: v

SWINBURN GIBSON WlLsoiv, JOHN S. SonorinLn.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

